The present invention relates to catheters used in angioplasty.
In an angioplasty procedure, an accepted and well known medical practice, a catheter is placed into the vascular system of the patient, by first inserting a needle percutaneously into a blood vessel, and then inserting a guide wire through the needle lumen into the blood vessel. The guide wire is maneuvered and steered through the vascular system until its distal end extends past the area to be treated. The needle can then be removed leaving the guide wire in place. A guide catheter can then be threaded over the proximal end of the guide wire and advanced along it until its distal end approaches the area to be treated. A guide catheter includes an elongated tubular portion that is open at its distal end and has a hub at its proximal end. The hub can be gripped by the physician as an aid in maneuvering the guide catheter into its desired position. The lumen extending through the guide catheter has a diameter that is large enough to accommodate the balloon catheter in its un-inflated form. The connection between the elongated tubular portion and the hub of the guide catheter is subjected to considerable force as the catheter is twisted, pushed and pulled during the positioning procedure. Since the distal end is open, blood flows up the elongated tubular portion and could leak through the juncture if the seal is defective. Unnecessary blood loss by the patient can not, in the best interest of the patient as well as operating room personnel, be tolerated. Furthermore the physician must grip the guide catheter hub in the positioning procedure and if blood is leaking through this juncture it will be difficult for the physician to control the catheter. The blood that has entered the guide catheter is forced out its distal end when the guide catheter is removed, and it is thus important that the blood not become contaminated while in the guide catheter. If a bonding agent is used to seal the juncture between the elongated tubular portion and the hub it is possible that the bonding agent could make contact with the blood and contaminate it. Although the chance of contamination is low a reliable seal that does not use a bonding agent eliminates this possibility completely. In addition the proper application of a bonding agent is a difficult task in the assembly of guide catheters and when it is not properly applied or for some reason does not result in a complete bond the product will not pass inspection and the product must be scrapped.
After the guide catheter has been positioned the guide wire can be removed if desired or left in place. With the guide catheter in place the balloon catheter is threaded through the lumen of the guide catheter. It exits the distal end of the guide catheter at a point approaching the area to be treated. The uninflated balloon portion of the catheter is located within the artery such that it crosses the stenoses or reduced area. Pressurized inflation fluid is directed to the inflatable balloon through a lumen formed in the catheter to thus dilate the restricted area. The inflation fluid is generally a liquid and is applied at relatively high pressures. As the balloon is inflated it expands and forces open the stenoses or reduced area of the artery.
It is a primary objective of the present invention to provide a guide catheter that can be assembled without the use of bonding agents.
Another objective of the present invention is to provide a self locking guide catheter that locks the components of the hub together and to the elongated tubular portion such that they can not become loosened accidently or inadvertently.
Another objective of the present invention is to provide a guide catheter that has a conical surface in the gripping area to facilitate maneuvering of the catheter by the physician.
These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art after having read the following detailed description of the preferred embodiment which are contained in and illustrated by the various drawing figures.